Safety device.



D. L. LINDQUIST.

SAFETY DEVICE.

APPLICATION FILED MAR. 16, ms.

Patented Apr. 15, 1919.

2 SHEETS-SHEET I.

D. L. LINDQUIST.

SAFETY DEVICE.

APPLICATION FILED MAR. 16. I916.

Patented Apr. 15, 1919.

2 SHEETS-SHEET 2.

BY L

ATTO

UNITED STA ES PATENT oEEroE.

DAVI 1;. Lr DeI'TIsT, 0E, ,YoixfxEzes, NEW, o'E i assieivon To one: ELE'vAEort COMPANY, 01? JERSEY CITY,11\TEW JERSEY, A CORPORATION OF JERSEY.

SAF TY DEVICE.

To all whom it mag/concern Beit known that I, DAVID L. LIND UIST, a subject of the King of Sweden, residing in Yonkers, in the county of Westchester and State of New York, have invented a new and useful Improvement in SafetyDevices, of which the following'is a specification;

My invention relates to an improvement in elevator safety devices, and provides a safety which will exert a practically constant retarding action on'the car-,regardless of variation of friction between the safety clamping jaws and the guide rails.

In the present day safety device, the. rail is gripped withapredetermined force and the braking effort exerted thereby on: the elevator car will depend on the intensity with which the rail is gripped and the coefiicie'nt of friction between the gripping means and the rail. The latter is a quantity depend-ing'on many circumstances, as for'instance, on the surface of the rail Whether rough or smooth, on theconsistency and nature of the rail lubricant, onthe material of the rail 'a'nd grip-ping mean-s, whether soft or hard,or Whether crystalline or-fibrous in structure. It is clear therefore that the intensity of the grip must be designed to bring car and'load to rest'with the least coefficient of friction. V V t In actual practice the frictional retarding force varies considerably and this' 'is mostly dueto rough or soft spbts-in the rail or lack of lubrication. Lack of lubrication, for in stance, frequently leads to seizure of the rail with the result that the car comes to rest with 'a'hard' jolt dangerous to life and-limb ofthe passengers. Moreover, the coefiicient of friction is never the same each of the two rails which guide the car, so that the braking'force exerted on one side of the 'car is alwaysl'arger'than' on the other side, and

frequently to such an extent thatthe car frame is bent out'ofshap'e.

The object of my invention is to obviate these defects and disadvantages and to so arrange the gripping mean th'at the retard ing force exerted. on thecar will be independent ofvariations" in the'coefiieient of friction. In other werasythe safety device as hereinafter described is'sc arranged that it will automatically adjust itself to exert a constant braking force irrespective of the conditions of the surface of the rail, its'hardness or lubrication.

Specification of Letters Patent.

Paten ed Apr. 15', 1919.

Application filed March 16, 1916'." se'ria'rm. 84,589.

Figure 1 .is a part sectional view of a safety plank carrying my device; Fig. 2- is a sectional view showing in detail my improved guide rail clamping means ininoperative' position; Fig. 3 is similar to Fig. 2, but shows the safety in operated position; Fig. 4 shows an elevator system wherein my device isused.

Referring to the drawings in detail, a drum, D, is carried by a safety plank, P, the plank being carried by the elevator car. The drum, which is mounted for rotation by a cable, 1, attached to a governorrope, 2, is bored" to receive "a sleeve member, S, the latter having a screw threaded bore to receive a screw threaded rod, 3. The endof the rod, 3, opposite to that entering the bore of the sleeve,S,;is also screw threaded and enters a-s'crew threaded bore in a gear 4. This gear forms art of a manual means for operating the saf gether the rod 3' and another screwv threaded rod 5, this rod being threaded oppositely to the rod, With this structure, when the drum, D, is rotated, therod 5 will be moved bodily longitudinally. On the end of the rod, 5', opposite to the screw threads, is mounted a wedge member adapted to engage rollers on the ends of levers 7 and 8, and as these levers are :pivoted'at 11, a longitudinal movement of the rod 5 to the left will force the wedge member between the rollers and cause the ends of the levers to separate. This forces the clamping members 9 and 10 on the other end of the levers toward the guide rails to grip'the same. This description is that of the left hand half of the safety plank. The other half of the safety'is the same, the rods 3 and 5 in this instance being threaded oppositely to the rods 3 and 5 just described, in order that they will travel oppositely to thetravel of the rods 3 and 5.

To actuate the drum, D, and thereby operate the safety, I have shown two means, illustrated in Fig. 4. One is automatic, the governor rope 2 being clamped between clamping members, 32, when the car overspeeds. Thisclamp action will stop the rope 2 andthe further travel of the car will exert a pull on the drum through the cable, 1, which as before pointed out is attached both to the d umand the governor rope. The other means for operating the safety is manual, in its operation, comprising a hand wheel 28' in the car, suitably geared to a ty, and also a coupling to couple tosprocket 29 on the plank, P, this sprocket carrying a gear meshing with a rack 30, which in turn engages a gear 31 connected to the drum, D. In both cases, therefore, the drum, D, will be rotated to cause the safety to operate.

Referring now to V posed between the outer ends ofthe members 7 and 8 and the guide rail, 13, are

.members 7 and 8, are rollers 14, 15, 16 and 17, these rollers normally resting on pins 18, 19, 20 and 21, provided for that purpose in the members 7 and 8. The lower ends of the wedge members are turned down to receive heavy coil springs, 24 and 25, which are retained in place by nuts 26 and 27 screwed on the lower end of the turned down portions, 22 and 23, theupper' ends of these springs bearing against the bottom of the members 7 and 8. I

: For best results I find that it is preferable to have the angle of inclination of the faces of the wedge members small, and the springs 24and 25 correspondingly long- The operation'of the safety is as follows: The forces actuating the clamping members 7 and 8 are transmitted through the rollers 14, 15, 16 and-17 onto the inclined surfaces of the wedges 9 and 10, they latter grip the rail and in turn will give rise to frictional forces which tend to cause the wedges to move upwardly relative to the clamping means and against the action of their respective springs 24 and 25. When the flanges 12 of the wedges fiengage with the rollers at the end of levers 7 and :8, the inward movement of the members 7 and 8 ceases and the latter remain stationary. At this instant the springs 24 and 25 have suffered a certain compression corresponding to the upward motion of the wedges 9., and 10, as shown in Fig. 3, and the braking force exerted on the car will depend on the spring compression and the coefficient of friction at the contact between wedges 9 and 10 and the rail. At any increase in the friction, say a rough spot on the rail, the wedges 9 and 10 tend to move upwardly, but since the clamp ing members 7 and 8 stay'stationary, .any upward movement would at once release the frictional engagement between the wedges 9 and 10 and the rail. Upon the release of the. frictional engagement. however, the

ment of the frictional engagement betweenthe wedge members 9 and 10 and the rail Figs.v 2 and 8. Interwill continue until the safety rides off the rough spot. The result of this action is to maintaintheretarding action fon the car practicallyconstant, and not"to -in'crease it as would be the case with the types of safe ties now in the art. V The springs 24 and 25 are preferably of a great number of turns. Owingto the fact that the clamping members 7 and 8, the wedges 9 and 10, and the rail have a certain elasticity, a slight upward motion of the. wedges from their position in Fig. 3 would not release the'frictional engagement. With a short spring, however, a slight. upward movement of the wedges would cause a material increase in the spring tension, and consequently in the retarding forceexerted on the car, and so asto maintain as nearly as possible a constant retarding force, long springs should be employed. -A long spring will in turn require a large upward movement of the wedges so as to createa sufficiently large spring compression. when the wedges move from their inoperative posiii ion in Fig. 2 to the operative position of *ig. 3. i 1

The advantage of a small wedge angle will now be appreciated, since for a given inward movement of the clampingmembers 7 and 8, the upward movement of thewedges 95 will be larger the smaller the wedge angle. I desire not to be limited to the precise details and arrangements of parts herein shown, as othersv skilled "in the art might make various changes therein without departing from the spirit and scope of my. in: vention. it

What I claim is 1 1. Ina earbrake or catch, a rail, engaging member having an inclined "face, means -.en-.

gaging said inclinedfaceto actuate said positioned relatively thereto that'relative movement of the two members above a predetermined amount tends to release the frictional engagement of the rail engaging member with the rail, and a spring between the 'twomembers, tending to return the railengaging member into" frictional engagement with the rail. 7

3. In a car brake or catch, the combination of a rail engaging member, a spring cars ried thereby, positively actuated means to actuate the rail engagmg member, inclined faces formed on the rail engaging member and the positively actuated means cooperating with each other and with the spring to maintain the friction of the rail engaging member on the rail practically constant.

4. In a car brake or catch, the combination of a wedge-shaped rail-engaging member,

having its thick end uppermost, and meansengaging the inclined face of said rail engaging member, the rail-engaging-member and the means engaging its inclined face having both a vertical and horizontal movement relatively to each other, and, a sprin interposed between the rail-engaging mem er and the means engaging the inclined face of the said rail-engagin member, the parts cooperating to maintain a practically uniform retarding action on the car.

5. In a car brake or catch, the combination of a wedge-shaped rail-engaging member, having its thick end uppermost, and means engaging the inclined face of said rail-en gaging member, the rail-engaging member and the means engaging its inclined face having a vertical movement relative to each other, said vertical movement causing a horizontal movement of one member relative to the other, a relatively upward movement of the rail-engaging member serving to decrease and a downward movement to increase the pressure on the rail inversely as the friction coefficient, and a spring between the rail engaging member and the means engagin its inclined face, the parts to maintain t e retarding action on the car practically uniform.

6. In a car brake or catch, the combination of a wedge-shaped rail-engaging member, having its thick end uppermost, and means having a longitudinal movement relative thereto, and a spring between the rail-engaging member and the said means, the parts cooperating together to maintain a practically uniform retarding action on the car.

7. In a car brake or catch, the combination of a wedge-shaped rail-engaging member having its thick end uppermost, and means having a longitudinal movement relative thereto and cooperating with the inclined face thereof, and a spring between the railengaging member and the said means, the parts coacting to maintain a practically constant retarding action on the car independent of Variation in friction between the rail engaging member and the rail.

8. In a car brake or catch, the combination of a wedge-shaped railengaging member, having its thick end uppermost, means between which and the rail-engaging member there is relative movement, both vertical and horizontal, and a sprin between the railengaging member and t c said means, the parts coacting to maintain the retarding action on the car practically constant.

9. In a car brake or catch, the combination of a wedge-shaped rail-engaging member, having its thick end uppermost, means between which and the rail-engaging member there is relative movement, both vertical and horizontal, a spring interposed between the rail-engaging member and the said' means, whereby the retarding action on the car will be maintained practically uniform.

10. In a car brake or catch, the combination of a wedge-shaped rail-engageable member, having a turned-down member extended from one of its ends, a nut on the said end, a wedge-shaped member for actuating the rail-engageable member, the faces that are opposite each other of the two members being inclined, rollers interposed between the inclined faces, pins on which the rollers'normally rest, a coiled spring on the turneddown member, bearing between the nut and the actuating member.

11. In a car brake or catch, the combination of a rail-engaging member having an inclined face, a spring carried thereby, a second member having an inclined face, the spring and the inclined faces of the two members cooperating to maintain the retarding action on the car practically constant.

In testimony whereof, I have signed my name to this specification in the presence of two subscribing witnesses.

DAVID L. LINDQUIST.

Witnesses:

WALTER C. SIRANG,

JAMES G. BETHEL.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. G. i 

